An investigation into the fire at a 2MW/2MWh lithium-ion energy storage system (ESS) in Arizona, US, is expected to close by the end of the year— eight months after the incident at the Arizona Public Service (APS) owned facility.
The final battery rack from APS’s McMicken site in Surprise is at a forensics laboratory in Michigan for analysis, after a specialty laboratory in Scottsdale removed it last month.
The majority of the battery cells in these modules had melted together, but the other electrical components were largely intact (these components have a higher melting point than other materials within the modules), said a statement from APS.
Investigators are alsoworking to determine if any shorting or other issues occurred around the components.
The statement read: “While the lab work is underway on the recovered hardware, third-party experts are working on modelling the explosion. This work will need to be compared and correlated with the lab findings to try to fully reconstruct what occurred.
“There are still many variables in the timing for completing all steps of this work, but the investigation team is targeting year-end to have more specific information important to recommending any precautions or modifications to other batteries on the APS system before returning them to service.”
Earlier this month, BEST Battery Briefing reported cities across Arizona had drawn up laws to guide the deployment of energy storage systems following a grid-scale battery storage facility fire in April.
Peoria, Phoenix and Surprise are enacting new laws that require homeowners, businesses and schools to apply for permits when installing ESSs.
The cities used the International Fire Code as a basis for the laws, making small changes depending on the location.
